Typhoid fever, caused by the bacterium Salmonella Enterica serotype Typhi, remains a significant global health concern, especially in areas with poor sanitation and limited access to clean water.
According to the National Health Service, one of the most challenging aspects of managing typhoid fever is its diagnosis. Unlike some other diseases with distinct symptoms, typhoid can mimic various other common illnesses in its early stages, making it difficult to identify promptly. Talking to the team of OnlyMyHealth, Dr Sanju Sidaraddi, Consultant, Pediatrician and Neonatologist, Motherhood Hospitals, Kharghar, Navi Mumbai shared several reasons why diagnosing typhoid fever can be particularly challenging:
Non-Specific Symptoms
Dr Sidaraddi said, “Typhoid fever presents with symptoms that are non-specific and can overlap with other febrile illnesses. Common symptoms include fever, headache, abdominal pain, malaise, and loss of appetite.”
The problem is that these symptoms are also seen in other infections like malaria, dengue, and influenza, making differential diagnosis difficult.
Clinical Similarities
The clinical presentation of typhoid fever can resemble other bacterial infections, said Dr Sidaraddi, such as brucellosis, tuberculosis, and pneumonia. He added, “Distinguishing between these diseases based on symptoms alone can be challenging.”
Lack of Specific Signs
“Unlike some infections that have characteristic signs (eg a rash in measles), typhoid fever lacks specific diagnostic signs,” said Dr Sidaraddi, adding that “The absence of a definitive clinical marker complicates diagnosis.”
Variable Incubation Period
Dr Sidaraddi said that the incubation period for typhoid fever can vary from about 6 to 30 days after exposure to the bacteria. He added, "This variability makes it challenging to pinpoint when symptoms may appear, further complicating the diagnosis process."
Laboratory Testing
Blood culture is the gold standard for diagnosing typhoid fever, said Dr Sidaraddi. However, blood cultures may yield false negatives, especially if antibiotics have been started before testing, he said. “Culturing the bacteria from bone marrow may be more sensitive,” said Dr Sidaraddi.
Serological Tests
Dr Sidaraddi said, “Widal test and Typhidot are commonly used serological tests. However, these tests have limitations, including low sensitivity and specificity.” False positives and cross-reactivity with other infections can occur, he added.
Geographic Variation
The prevalence of typhoid fever varies geographically according to Dr Sidaraddi. “In areas where typhoid is endemic, clinicians may have a higher index of suspicion. However, in non-endemic regions, typhoid fever may not be considered initially,” he said.
Travel History
One other challenge with typhoid is that travelers may not always disclose their travel history, said Dr Sidaraddi. “Obtaining a detailed travel history is crucial to diagnose typhoid because patients who have recently travelled to endemic areas are at higher risk,” he added.
Also Read: Dengue And Typhoid Co-Infection: Understanding The Difference And Ways To Manage Symptoms
Dr Sidaraddi concluded that accurate diagnosis of typhoid fever requires a combination of awareness of risk factors, a high degree of clinical suspicion, a detailed history, clinical examination, and laboratory tests. Clinicians must consider typhoid fever in the differential diagnosis of febrile illnesses, especially in endemic regions.